The principle for releasing volatile tobacco components on which HNB smoking articles are based is fundamentally different to that behind conventional smoking articles, in which the components are released by burning the tobacco. In what are referred to as HNB (heat not burn) smoking articles, the tobacco components are instead released by hot gases passing through the tobacco and/or by heating the tobacco, and therefore the amounts of the smoke components that were previously inevitably released when burning the tobacco are at least significantly reduced, or said components can even be eliminated completely. For this purpose, a heat source is provided in the HNB smoking article that is arranged on the end of the HNB smoking article that is remote from the mouth piece, i.e. upstream of the tobacco in the drag direction, and therefore the gases heated by the heat source flow through the tobacco and heat the tobacco, and the volatile components are removed from the tobacco in the process. The tobacco can also be heated directly by the heat source.
HNB smoking articles are composed of a plurality of subunits or also segments that are held together by one or more cover strips. In addition to the above-described segments, namely the heat source and the tobacco segment, a cavity is provided between the heat source and the tobacco segment, which cavity is filled with a flavouring agent or catalyst in the form of loose pellets or fibres. The hot gases generated by the heat source then flow through the flavouring agent or catalyst before flowing through the tobacco, and therefore the hot gases flowing from the heat source can be positively influenced such that they have an improved taste or such that the number of components that are harmful to health is reduced. Furthermore, in order to outgas the components from the tobacco, comparatively high temperatures have to be brought about by the gases heated by the heat source or by directly heating the tobacco, and therefore a cooling portion can also be provided downstream of the tobacco, in which cooling portion the gases leaving the tobacco are subsequently cooled so that the consumer does not burn his mouth when smoking.
HNB smoking articles of this type are known, in principle, from US 2011/0041861 A1, US 2004/0173229 A1 and EP 2 777 408 A1.
EP 2 777 408 A1 in particular discloses forming the cavity by wrapping a flexible cover strip around the heat source and sticking said cover strip, by a projecting axial length, to the rod-shaped heat source. For this purpose, the cover strip is provided with an L-shaped adhesive joint and is adhered to the rod-shaped heat source by one leg of the L-shaped adhesive joint, and the two free edges of the cover strip that come to overlap one another are adhered to one another by means of the other leg of the L-shaped adhesive joint such that the cover strip is cylindrical. The projecting axial length of the cover strip then forms a cylindrical cavity that opens into an end face of the first subunit.
This solution is disadvantageous in that, in a first step, the cover strip is adhered to the heat source by means of the L-shaped adhesive joint in a point by point manner, and therefore if the cover strip is pulled at an angle and is thus obliquely oriented, it is adhered to the heat source in a correspondingly crooked manner. Furthermore, the cover strip has to be correspondingly flexible in order for it to be possible to wrap it around the heat source; however, this has an adverse effect on a subsequent cutting process because, owing to the flexibility thereof, the cover strip has a tendency to become slack during the cutting process. Therefore, a significant amount of effort is required in order to produce a clean cut—that is if this is even possible. Furthermore, the cavity formed by the projecting axial length of the cover strip is subsequently filled with pellets or fibres of a flavour carrier or a catalyst, for which purpose the heat source together with the adjoining cavity formed by the cover strip has to be oriented vertically, there being a cavity that is open at the top, in order for it to be possible to fill the cavity with the pellets or fibres from above in a manner which is beneficial in terms of process. However, this filling process can be made more difficult in undesirable conditions if the flexible cover strip is deformed by kinking, for example, and the cavity thus cannot be accessed from the top in a completely free manner.